Electromagnetic Wave Absorption Properties Research Articles

Hierarchically flower-like structure assembled with porous nanosheet-supported MXene for ultrathin electromagnetic wave absorption

The design of a hierarchical three-dimensional (3D) structure is beneficial to suppressing the accumulation of MXene flakes and obtaining satisfactory lightweight, efficient, and broadband-absorbing materials. Undoubtedly, the exploration of electromagnetic wave (EMW) absorbing materials with stronger absorption and thinner thickness of multi-component and multi-mechanism synergy is in great demand, but it is still a challenge. In this paper, we report for the first time a well-designed and optimized electrostatic self-assembly anchored Ti3C2Tx nanosheet to prepare porous flower-like Co/ZnO@CMWCNTs/Ti3C2Tx (CZCT) composites. The electromagnetic parameters and EMW absorption properties of carboxylated multi-walled carbon nanotubes (CMWCNTs) and Ti3C2Tx nanosheets can be controlled by adjusting the load of CMWCNTs and Ti3C2Tx nanosheets. Based on the multi-dimensional material collaboration and electromagnetic synergistic strategy, the flower-like CZCT composite achieves a significant minimum reflection loss (RLmin) of −46 dB at a thickness of 1.5 mm. The maximum effective absorption bandwidth (EABmax) of 4 GHz is 1.9 mm. This work provides a simple strategy for building MXene-based composites to achieve efficient EMW absorption materials with lightweight and adjustable EAB.

Electromagnetic wave absorption properties of Ca1-xCexFe0.5Mn0.5O3–δ ceramics prepared by a sol–gel combustion method

In this study, porous Ce-doped CaFe0.5Mn0.5O3–δ(CFMO) with good microwave absorption properties is reported for the first time. Herein, CexCa1−xFe0.5Mn0.5O3−δ (x = 0, 0.05, 0.1, 0.15) (Ce-CFMO) sample powders were prepared by sol–gel method after calcination at 750 °C. Ce-CFMO was characterized by XRD, SEM, TEM, XPS, and VSM, and the Ce-CFMO was also mixed with paraffin wax for VNA. The addition of Ce led to enhanced porosity, enhanced interfacial polarization, enhanced defect polarization, and higher oxygen vacancy content in the CFMO. This resulted in enhanced charge polarization and dipole polarization as well as significant optimization of the impedance matching of CFMO. The unique pore structure of the CFMO is the main reason for its microwave absorption performance. Moreover, the preparation method of this material is simple and its cost is low, providing it with wide application prospects. CFMO has not yet been applied in the field of microwave absorbing materials, and there is still a lot of room for development in the future.

3D flower-like hollow CuS@PANI microspheres with superb X-band electromagnetic wave absorption

• Novel 3D flower-like hollow CuS@PANI micropheres have been successfully synthesized via a solvothermal process followed by in-situ polymerization. • The excellent reflection loss of 3D flower-like hollow CuS@PANI micropheres is −71.1 dB with a matching thickness of 2.75 mm. • The effective absorption bandwidth of 3D flower-like hollow CuS@PANI micropheres almost cover the whole X-band. Superior electromagnetic (EM) wave absorption properties in 8.2–12.4 GHz ( X -band) can be obtained via the effective combination of polyaniline (PANI) and CuS. Herein, novel 3D flower-like hollow CuS@PANI microspheres were fabricated by a solvothermal process followed by in-situ polymerization. EM wave absorption properties of 3D flower-like hollow CuS@PANI microspheres in X -band were systematically studied, indicating the minimum reflection loss ( RL min ) of -71.1 dB and effective absorption bandwidth (EAB) covering 81% of test frequency range were achieved with a thickness of 2.75 mm. Excellent EM wave absorption properties of 3D flower-like hollow CuS@PANI microspheres were mainly ascribed to outstanding impedance matching characteristic and dielectric loss capability (conduction loss, interfacial polarization loss and dipole polarization loss). Moreover, due to the distinctive flower-like hollow structure of CuS@PANI microspheres, an additional wave-absorbing mechanism was provided by increasing the transmission paths of EM waves.

Construction of 1D biomass-derived tubular carbon fiber/Ni nanoparticles composite for broadband and lightweight microwave absorbers

The novel electromagnetic wave (EMW) absorber puts forward higher requirements for broadband and lightweight. Compared with other options, the construction of system for low-dimensional composite material is an effective way to realize this aspiration. In this research, making using of Typha's fluff as a template, 1D tubular carbon fiber/Ni nanoparticles composite (TN) was rationally constructed to achieve the remarkable electromagnetic wave absorption (EMA) properties through green and simple synthesis process. The low percolation threshold of the carbon fiber ensures sufficient conduction loss effects of TN at a low filling ratio to achieve the goal of lightweight. The design of the magnetic-dielectric synergistic system is more conducive to the acquisition of excellent impedance matching. The uniform distribution of in-situ grown nickel nanoparticles provides a magnetic coupling network and forms a rich heterogeneous interface with the carbon fiber to enhance interfacial polarization. These facilitate the broadband absorption behavior of composite. Accordingly, TN exhibits impressive EMA properties with an EAB of 8.6 GHz and a RL of −56.4 dB with a filling ratio of only 10 wt%. These inspiring achievements light the way to the progress of the novel EMW absorbers, including the high targets of ultra-light and ultra-wide. • 1D tubular carbon fiber/Ni nanoparticles composites were obtained via carbonization process and in-situ hydrothermal method. • A minimum RL of up to −56.4 dB and an EAB of 8.6 GHz with a filling ratio of only 10 wt% was achieved. • The characteristic tubular carbon skeleton of Typha's fluff guarantees the formation of a well-conducting network of TN composites at a low over-permeation threshold.

Lightweight 3D interconnected porous carbon with robust cavity skeleton derived from petroleum pitch for effective multi-band electromagnetic wave absorption

Ingenious porous skeleton design is highly desired for advanced carbonaceous electromagnetic wave absorbers (EWAs) to address the issues of impedance mismatch and enhance attenuation ability. Herein, a controllable structure of petroleum pitch-derived coral-like 3D interconnected porous carbon (PC) framework is constructed in one step by a hard-template method. The well-designed air-filled 3D interconnected cavity structure provides ideal impedance matching for absorbers and facilitates the multiple scattering of electromagnetic waves, while continuous robust carbon skeleton exhibits a satisfied electrical conductivity (≈553 S/m), greatly boosting the electrical energy loss capability of PCs. Therefore, even under an ultralow filler loading of only 6 wt%, the corresponding minimum reflection loss (RL) values of multiple thicknesses are all below −20 dB in the range of 1.5–5.0 mm, and the strongest RL of PCs reaches −50.04 dB (matching thickness is 2.37 mm), the widest effective absorption bandwidth is up to 4.4 GHz. The overall performance outperforms most of previously reported carbon-based EWAs. This synthetic strategy presents a broad application prospect due to its simple preparation method and lost-cost raw materials, and provides a new route for the design of advanced lightweight absorbers from abundant inferior heavy oil. Lightweight 3D interconnected porous carbon material with robust cavities skeleton is prepared by a facile template method and yields excellent multi-band electromagnetic wave absorption at an ultralow filler loading. • 3D porous carbon framework with robust cavity skeleton is prepared by a facile salt template strategy. • 3D interconnected cavity structure endows porous carbon with strong conduction loss and excellent impedance matching. • Porous carbon yields a high electromagnetic wave absorption property (−50.04 dB) at an ultralow filler loading of 6 wt%. • Highly-efficient multi-band electromagnetic wave absorption has been achieved by simply tuning the thickness. • This work offers a new route for the design of advanced carbon-based absorbers from low-cost petroleum pitch.

Enhanced broadband microwave absorption of Fe/C core-shell nanofibers in X and Ku bands

Fe/C core-shell nanofibers were prepared via a coaxial electrospinning technique integrated with high-temperature carbonization, in which the Fe(NO3)3-containing PAN solution and Fe(NO3)3 constituted the shell and core structures, respectively. The core-shell structure was perfectly maintained after carbonization, and Fe nanoparticles were uniformly distributed within the carbon nanofibers. The effects of the microscopic morphology and crystallinity of the carbon components on the electromagnetic properties, matching characteristics, and electromagnetic wave absorption properties of the Fe/C nanofibers were investigated by adjusting the carbonization temperature. As-prepared Fe/C-800 °C core-shell nanofibers mixed with 10 wt% of paraffin showed a minimal reflection loss (RLmin) of −20.6 dB under 11.52 GHz at 2.5 mm of thickness and lower than −20 dB under 2.3–5.0 mm of thickness. The efficient absorption bandwidth (EAB) was 6.24 GHz in the range of 11.76–18 GHz at 2.1 mm, covering the whole Ku band. The absorption bandwidth can cover the whole X and Ku bands by varying the sample thickness. The efficient absorption bandwidth was 3.84 GHz in the range of 8.08–11.92 GHz at 2.9 mm, covering the X band. The effective complementarities between the magnetic loss of Fe nanoparticles, the dielectric loss of PAN-based carbon, and the core-shell structure promoted impedance matching and multiple interface polarization, endowing the produced composites with prominent absorption characteristics of microwaves. Therefore, the prepared Fe/C core-shell nanofibers are an ideal lightweight and broadband electromagnetic wave (EMW)-absorbing material that exhibits high-performance microwave absorption.

Ni/Ni3ZnC0.7 modified alginate-derived carbon composites with porous structures for electromagnetic wave absorption

Electromagnetic wave (EMW) absorption materials with both high-performance and low-cost are demanded to reduce unwanted noise at microwave communication frequencies. Herein, Ni/Ni3ZnC0.7 modified alginate-derived carbon (Ni/Ni3ZnC0.7/C) composites were successfully prepared by constructing a Ni2+-Zn2+-alginate gel, followed by freeze-drying and carbonization processes. The co-introduction of nickel and zinc greatly improved EMW absorption properties. By adjusting the amounts of Ni2+ and Zn2+ ions, Ni/Ni3ZnC0.7/C composites with excellent impedance matching and EMW absorption performance were realized, evidenced by a maximum reflection loss of −40.2 dB (14.8 GHz, 2.0 mm) and an effective absorption bandwidth of 5.4 GHz (12.6–18.0 GHz, 2.0 mm). This work provides a very simple and green strategy for designing lightweight and high-performance EMW absorbers offering considerable potential for practical applications.

Double salt-template strategy for the growth of N, S-codoped graphitic carbon nanoframes on the graphene toward high-performance electromagnetic wave absorption

The increasingly serious electromagnetic radiation urgently call for high performance electromagnetic wave (EMW) absorbers. Hollow carbon nanostructures are promising for lightweight EMW absorbers. However, due to lack of sufficient polarization centers, the EMW absorption property of hollow carbon nanosturctures is still unsatisfactory. Herein, we develop a double-salt template method for fabrication of N, S-codoped graphitic carbon nanoframes (GF) that anchored on the graphene sheets (GS). The GFs in the sample (N, S-GF/GS) have a width of about 51 nm and a wall thickness of only 4.8 nm. Furthermore, the graphene plane in the GF is perpendicular to the graphene plane in the GS, leading to the formation of numerous interfaces between the graphene planes perpendicular to each other. Theoretical calculations indicate that the interfaces can induce the interfacial polarization loss, and the N, S co-doping can cause dipole polarization loss, both of which enhance the EMW absorption performance of the N, S-GF/GS. The minimal reflection loss and efficient absorption width of the N, S-GF/GS at a low filler ratio of 10 wt% are -45.64 dB at the matching thickness of 2.3 mm and 4.35 GHz with the thickness of 1.5 mm, respectively, superior to most of carbon-based absorbers. Our proposed method opens a promising way for high-performance EMW absorbers.

Synthesis and electromagnetic wave absorption properties of Gd-Co ferrite@carbon core–shell structure composites

Synthesis and electromagnetic wave absorption properties of Gd-Co ferrite@carbon core–shell structure composites

Texture Regulation of Metal-Organic Frameworks, Microwave Absorption Mechanism-Oriented Structural Optimization and Design Perspectives.

Texture regulation of metal-organic frameworks (MOFs) is essential for controlling their electromagnetic wave (EMW) absorption properties. This review systematically summarizes the recent advancements in texture regulation strategies for MOFs, including etching and exchange of central ions, etching and exchange of ligands, chemically induced self-assembly, and MOF-on-MOF heterostructure design. Additionally, the EMW absorption mechanisms in approaches based on structure-function dependencies, including nano-micro topological engineering, defect engineering, interface engineering, and hybrid engineering, are comprehensively explored. Finally, current challenges and future research orientation are proposed. This review aims to provide new perspectives for designing MOF-derived EMW-absorption materials to achieve essential breakthroughs in mechanistic investigations in this promising field.

The electromagnetic wave absorption properties of woven glass fiber composites filled with Sb2O3 and SnO2 nanoparticles doped mica pigments

AbstractIn this study, the electromagnetic wave absorption properties of woven glass fiber reinforced epoxy composites with Sb2O3 and SnO2 nanoparticles doped mica pigments were investigated. Herein, we synthesized SnO2/mica, Sb2O3/mica, and Sb2O3:SnO2/mica pigments using the sol–gel method. Subsequently, mica pigments filled glass fiber/epoxy composite panels were fabricated with a vacuum assisted resin mold. The phase, crystal, and morphological examinations of particles confirm the deposition of SnO2 and Sb2O3 nanoparticles on the mica surfaces. The electromagnetic wave absorption properties of samples were measured using the S parameters and obtained dielectric data. Sb2O3:SnO2/mica particles display higher complex permittivity and dielectric loss values due to the strong interfacial polarization between conductive nano metal‐oxide shells and mica surfaces. According to the calculated reflection loss values, Sb2O3:SnO2/mica particles exhibit superior electromagnetic wave absorption performance with a minimum reflection loss of −25.62 dB for 2.4 mm thicknesses with effective bandwidth between 9.3 and 12.4 GHz. The S parameters of the prepared structural composites with the size of 30 cm × 30 cm × 3 mm was determined by the free‐space technique using the transmission line technique. According to the S12 parameters, filled glass fiber/epoxy composite containing 25 wt% Sb2O3:SnO2/mica show a minimum reflection loss of −20.426 dB at 8.2 GHz with effective bandwidth between 8.2 and 9.67 GHz. These results indicate that Sb2O3:SnO2/mica‐filled fiber/epoxy composite is an excellent candidate for the practical application of electromagnetic wave absorbers.

Synthesis and Electromagnetic Wave Absorbing Properties of Ni-substituted Z-type Hexaferrite-epoxy Composites

Ni-substituted Z-type hexaferrites with the chemical formula Sr₃CoSUB2-x/SUBNiSUBx/SUBFeSUB24/SUBOSUB41/SUB (x = 0, 0.1, 0.2, 0.3, 0.4, 0.5) were prepared by solid-state reaction processes. XRD analysis revealed that nearly a single Z-type hexaferrite phase could be obtained for the samples with Ni substitution x ≤ 0.5 when the samples were twice calcined at 1160 and 1235 °C, respectively, in air. The complex permittivity (ε

Carbon doped with binary heteroatoms (N,X–C, where X = P, B, or S) derived from polypyrrole for enhanced electromagnetic wave absorption at microwave frequencies

Dual heteroatom-doped carbon materials show great promise as electromagnetic wave absorbers. However, synthesizing carbons containing multiple heteroatoms at controlled heteroatom doping levels has provided challenges to date. Herein, we report a simple method for manufacturing dual heteroatom doped carbons (N,X–C, where X = P, B, or S) by direct carbonization of polypyrrole synthesized in the presence of H3PO4, H3BO3, or H2SO4, respectively. The heteroatom content of the N,X–C products could be precisely tuned by varying amounts of acid dopant used in the polypyrrole synthesis. The N,X–C materials showed excellent electromagnetic wave absorption properties, especially N,S1–C (prepared using equimolar amounts of pyrrole and H2SO4) which offered a wide absorption bandwidth up to 6.6 GHz (11.38–18 GHz), and a RLmin of −32.3 dB (14.2 GHz) at 2.5 mm at a filler loading of 9.0 wt%. The outstanding electromagnetic wave absorption performance of N,S1–C was attributed to the presence of N dopant species, defects, C–S, and C–SOx groups, which optimized dipole polarization and conduction loss in the dielectric loss leading to excellent impedance matching.

Hydro/Organo/Ionogels: "Controllable" Electromagnetic Wave Absorbers.

Demand for electromagnetic wave (EMW) absorbers continues to increase with technological advances in wearable electronics and military applications. In this study, a new strategy to overcome the drawbacks of current absorbers by employing the co-contribution of functional polymer frameworks and liquids with strong EMW absorption properties is proposed. Strongly polar water, dimethyl sulfoxide/water mixtures, and highly conductive 1-ethyl-3-methylimidazolium ethyl sulfate ([EMI][ES]) are immobilized in dielectrically inert polymer networks to form different classes of gels (hydrogels, organogels, and ionogels). These gels demonstrate a high correlation between their dielectric properties and polarity/ionic conductivity/non-covalent interaction of immobilized liquids. Thus, the EMW absorption performances of the gels can be precisely tuned over a wide range due to the diversity and stability of the liquids. The prepared hydrogels show good shielding performance (shielding efficiency > 20dB) due to the high dielectric constants, while organogels with moderate attenuation ability and impedance matching achieve full-wave absorption in X-band (8.2-12.4GHz) at 2.5 ± 0.5mm. The ionogels also offer a wide effective absorption bandwidth (10.79-16.38GHz at 2.2mm) via prominent ionic conduction loss. In short, this work provides a conceptually novel platform to develop high-efficient, customizable, and low-cost functional absorbers.

X-band electromagnetic absorption and mechanical properties of mullite/Ti3AlC2 composites

Aiming to enhance the electromagnetic wave absorption (EWA) property of mullite ceramics, MAX phase of Ti3AlC2 was introduced into mullite ceramics for the first time. Significantly improved EWA and mechanical performance of mullite ceramics were achieved simultaneously by introducing Ti3AlC2 via a pressureless sintering process. Results indicated the increasing sintering temperature promoted the densification of as-prepared composites and induced the decomposition of Ti3AlC2 to different degrees. The composites sintered at 1450 °C possessed the optimal mechanical performance with flexural strength, fracture toughness and Vickers hardness of 211.78 MPa, 5.28 MPa m1/2 and 9.36 GPa, respectively. The improved mechanical properties were mainly attributed to the enhanced densification and even-distributed TiC particles in the mullite matrix. Moreover, polarization loss resulting from the unpaired defect and newly formed interfaces, and conductance loss originating from the highly conductive TiC particles, played a major role in the considerable improvement in EWA properties of mullite-based composites. The minimum RL value of composites sintered at 1450 °C reached −35.5 dB with a thickness of 2.65 mm. By regulating the decomposition degree of Ti3AlC2, the mechanical and EWA performance of mullite ceramics can be effectively enhanced. This study will provide an effective reference for the preparation of EWA materials with excellent comprehensive properties.

Facile synthesis of core-shell structured C/Fe3O4 composite fiber electromagnetic wave absorbing materials with multiple loss mechanisms.

The use of heterostructures in electromagnetic wave absorption applications has been limited by the problem of homogeneous dispersion in composites. In this study, three-dimensional (3D) cross-linked electromagnetic wave absorbing composites with the carbon nanofiber/Fe3O4 (CNF/Fe3O4) core-shell structure were synthesized by expanding the interface of the heterogeneous structure with Fe3O4 nanocrystals uniformly modified on the surface of the carbon nanofiber. The 3D cross-linked structure of the composites contributes to the generation of conductive loss and macroscopic eddy current loss. The heterogeneous interface formed by graphite nanocrystals and amorphous carbon in the carbon nanofiber is identified by high-resolution transmission electron microscopy and Raman spectroscopy as having a strong electromagnetic wave absorption capacity for boundary-type defects. The Fe3O4 nanocrystal particles on the surface of the carbon nanofiber not only have the strong magnetic loss capability of magnetic materials but also form a new heterogeneous interface with the carbon nanofiber surface, which further enhances the interfacial polarization of the composite and improves the electromagnetic wave absorption properties. With the synergistic effects of interfacial polarization, macroscopic and microscopic eddy current losses, conductive losses, and magnetic losses, the electromagnetic wave absorption performance of the composites is further enhanced based on the carbon nanofiber. The reflection loss reaches -51.11, -42.99, and -55.98 dB at 9, 12 (X-band), and 17GHz (Ku-band), respectively, corresponding to the thicknesses of 2.0, 1.5, and 1.0mm. In addition, the widest effective absorption bandwidth is 3.3GHz at 14.7-18GHz (only 1.09mm).

Achieving electromagnetic wave absorption capabilities by fabrication of flower-like structure NiCo2O4 derived from low-temperature co-precipitation

In this work, The NiCo2O4 with 3D hierarchical multilayer flower-like structure was prepared by the low-temperature (55 °C) co-precipitation method combined with the calcination process, avoiding the traditional high-temperature hydrothermal synthesis method. The prepared flower-like NiCo2O4 with a large specific surface area was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and automatic surface area and porosity analyzer (BET) and vector network analyzer (VNA). A novel evaluation approach was proposed to evaluate the electromagnetic wave (EMW) absorbing properties of various samples (different calcination temperatures), which was to defined the ΔS as the area enclosed by the curve when the reflection loss (RL) value was less than −10. In order to take the material thickness into account, and then the effective reflection loss (RLE) value was defined ΔS/d to measure the electromagnetic wave (EMW) loss capability of the different samples. The results showed that NiCo2O4 exhibited excellent EMW absorption effect when the calcination temperature was 400 °C, and the maximum RL value reached −43.17 dB at 14.32 GHz with the thickness of 1.5 mm and the effective absorption bandwidth (fe) was 4.48 GHz (12.08 GHz–16.56 GHz). The excellent EMW absorption property was mainly due to NiCo2O4 with particular porous flower-like structure, which could achieve impedance matching to loss EMW by dielectric loss and magnetic loss.

Tailorable microwave absorption properties of macro-porous core@shell structured SiC@Ti3SiC2 via molten salt shielded synthesis (MS3) method in air

High-performance microwave absorption and lightweight design have evolved into the foremost critical considerations in the practical application of modern microwave absorbing materials. In view of this, macro-porous core-shell structured SiC@Ti3SiC2 were prepared through a facile molten salt shielded synthesis method in air. Distinctly, the minimum reflection loss (RL) value of SiC@Ti3SiC2 could reach − 68.59 dB at 9.76 GHz with the bandwidth of RL< −10 dB of 5.6 GHz when the absorber thickness is 2.3 mm. The synergistic mechanism of the multiple scattering, conductive loss, and significant polarization effects of macro-porous (average 53 nm) core-shell structured SiC compounded with nano-layered Ti3SiC2 (∼60 nm) is reviewed for the considerable improvement of electromagnetic wave absorption properties. This work provides a practical reference for the design and synthesis of high-performance Ti3SiC2-based microwave absorbers.

Sandwich-like preparation of Ti3C2Tx@CoFe@TiO2 nanocomposites for high-performance electromagnetic wave absorption

Electromagnetic wave (EMW) absorbing materials have been widely applied in the fields of military and engineering areas. It is of great significance to develop high-performance EMW absorbing materials. This work assembled the sandwich-like Ti 3 C 2 T x based nanocomposites by the microwave-assisted annealing of CoFe-MOF@Ti 3 C 2 T x (CFMF@Ti 3 C 2 T x ) precursors at different temperatures. Results show that, as the heat treatment temperature is 450 °C, the sandwich-like Ti 3 C 2 T x @CoFe@TiO 2 nanocomposites present better EMW absorption properties. The minimum reflection loss (RL) value was −62.9 dB at 17.95 GHz with a thin thickness of 1.2 mm. Moreover, the effective absorption bandwidth (EAB) value was 5.02 GHz (12.74–17.76 GHz) with a thickness of 1.4 mm. The application of microwave-assisted annealing contributed to the formation of CoFe nanoparticles and TiO 2 nanoparticles because of the ultra-fast heating rate. The introduction of the nanoparticles enhanced the multiple polarization, optimized the impedance matching and introduced magnetic loss, leading to the improvement of EMW absorption. When the annealing temperature further increased to 550 °C, the EMW absorbing performance was weakened, which was mainly correlated with the decrement of the interface area due to the increase of the TiO 2 nanoparticle size and CoFe nanoparticle size. Thus, the loss effect of the multiple interface polarization weakens in the EMW absorption. In addition, the high permittivity of Ti 3 C 2 T x disappears, which deteriorated the impedance matching and attenuation ability of EMW. Ultimately, sandwich-like Ti 3 C 2 T x @CoFe@TiO 2 nanocomposite with satisfactory EMW absorbing properties is established, promising for various EMW absorbing applications.

Construction of SnO2 nanoparticle cluster@PANI core-shell microspheres for efficient X-band electromagnetic wave absorption

Superior electromagnetic (EM) wave absorption properties in 8.2–12.4 GHz (X-band) can be obtained via the effective combination of polyaniline (PANI) and SnO 2 nanoparticle cluster. In this work, SnO 2 nanoparticle cluster@PANI (SnO 2 @PANI) core-shell microspheres were firstly fabricated via a hydrothermal process followed by in-situ polymerization, and the EM wave absorption properties of SnO 2 @PANI core-shell microspheres in X band were studied. The related structure and morphology analyses indicated SnO 2 @PANI core-shell microspheres were successfully synthesized with PANI coated on the surface of SnO 2 nanoparticle cluster. The minimum reflection loss (RL min ) of − 69.1 dB (thickness of 2.78 mm) and effective absorption bandwidth (EAB) covering the whole X-band (when the thickness was from 2.5 to 3.1 mm) was achieved. Remarkable EM wave absorption properties of SnO 2 @PANI core-shell microspheres were mainly attributed to the outstanding impedance matching characteristic and dielectric loss capability (conduction loss, interfacial polarization loss and dipole polarization loss). • SnO 2 @PANI core-shell micropheres have been synthesized via a hydrothermal process followed by in-situ polymerization. • The excellent reflection loss of SnO 2 @PANI core-shell micropheres is − 69.1 dB with a matching thickness of 2.78 mm. • The effective absorption bandwidth of SnO 2 @PANI core-shell micropheres could cover the whole X-band.